Java about the hasNextXxx() method in the Scanner class

The hasNextXxx() method is often used to determine whether the next input content belongs to Xxx

and return a boolean value (true or false)

import java.util.Scanner;

public class pd {
    public static void main(String[] args){
        Scanner sc=new Scanner(System.in);
        boolean b=sc.hasNextInt();
        char c=sc.next().charAt(0);
        System.out.print(b);
    }
}

Enter j return value is false

 Therefore, it is often used as a judgment condition in an if statement or a loop statement

import java.util.Scanner;

public class pd {
    public static void main(String[] args){
        Scanner sc=new Scanner(System.in);
        System.out.print("请输入成绩：");
        if(sc.hasNextInt()){
            int a =sc.nextInt();
            System.out.println("你的成绩是："+a+"分");
        }else {
            System.out.println("输入错误，请输入数字！");
        }
    }
}

Initially enter the char type

There seems to be no nextChar() method in Scanner in java

It only provides the input method of String String class

But java provides a nice workaround

The charAt(n) method can return the character at the nth position of the string (n starts from 0)

So we can use this method to implement char type input

import java.util.Scanner;

public class pd {
    public static void main(String[] args){
        Scanner sc=new Scanner(System.in);
        char a=sc.next().charAt(0);
        System.out.print(a);
    }
}